1. Field of the Disclosure
The present disclosure relates to a coordinate detecting device and a coordinate detecting program, and more particularly, to a coordinate detecting device and a coordinate detecting program related to an operation on a screen.
2. Description of the Related Art
In recent years, a device including a coordinate detecting device which specifies a position where the finger touches to operate an electronic apparatus has been actively developed in electronic apparatuses, such as a computer, a mobile phone terminal, and a PDA (Personal Digital Assistant).
For example, as the device including the coordinate detecting device, there is a pointing device (coordinate input device) which is called a pad, a touch pad, or a track pad provided in the computer. The coordinate input device is incorporated into a portable notebook personal computer or is attached to the outside of a desktop computer, and is then used. In this case, it is not necessary to move the coordinate input device, unlike a mouse. Therefore, it is possible to operate the coordinate input device in a limited space, such as on a desk, without any difficulty.
For example, in a portable apparatus, such as a mobile phone terminal or a PDA in which the coordinate detecting device is incorporated into a display screen, the user can directly touch the display screen (operation surface) with the fingers to perform a desired operation.
For example, as the coordinate detecting device, there is a device which uses a variation in capacitance formed between an electrode and a portion around the electrode due to the contact of the finger of the user. In general, a capacitance-type coordinate detecting device includes a plurality of electrodes that are arranged in a matrix in the X-axis direction and the Y-axis direction and a detecting unit that detects the capacitance of each electrode, and detects electrodes with a large capacitance variation in the X-axis direction and the Y-axis direction among the plurality of electrodes, thereby specifying the position where the user touches.
As a capacitance-type coordinate detecting method, for example, a method has been proposed which calculates coordinates on the basis of the position of the centroid of an effective region with a capacitance variation equal to or greater than a predetermined value (for example, JPA-2010-244302).
However, for example, in a capacitance-type touch pad, in some cases, the finger which does not directly touch the operation surface, but approaches the operation surface has a great effect on a change in the capacitance of the electrode. In addition, in some cases, a large variation occurs in the touch area depending on the method of touching the operation surface with the finger. In this case, when the coordinates are constantly calculated on the basis of the position of the centroid, the detected coordinates are changed by the influence of the finger which does not touch the operation surface or depending on the method of touching the operation surface with the finger, which may cause a reduction in the detection accuracy of the coordinates.